1. Field of the Invention
The present invention relates to a hinge device for-a flat panel display, and more particularly to a novel hinge device, which enables the display panel to be adjusted and retained at any desired angle.
2. Description of Related Art
As known in the art, common flat panel displays such as liquid crystal display (LCD), and thin-film transistor (TFT) liquid crystal display etc. are widely used incorporating with PC personal computers or NB notebook computers or the likes due to its lightweight and small thickness and small size properties. A known hinge device used between a display panel and a pedestal base generally comprises a spindle extending through connecting parts respectively provided at pivotal ends of the display panel and the base, and disc washers and screw nuts mounted around the spindle, whereby a friction is produced while the display panel pivots with respect to the base. Alternatively, the display panel of a NB computer may also be retained at any angle by a friction produced by means of a hinge device employing tight fit between a sleeve and a spindle. However, it can be understand that the friction between the display panel and the pedestal base of the Notebook (NB) computer tends to be reduced after having been used for a long time, and external contacting surface of the metal-made spindle and corresponding internal contacting surface of the plastic sleeve may be grinded, whereby the positioning of the display panel may lose balance.
A prior art as shown in FIGS. 1a and 1b illustrates a hinge device (1), which is mounted with a connecting supporter secured at a backside of an LCD display panel. The hinge device (1) generally comprises a connecting member (10), a spindle (20), a pair of retaining plates (30), a pair of supporting units (40), a pair of internal springs (50), a pair of external springs (60) and a pair of screw nuts (70).
The connecting member (10) has a connecting portion (11) formed at one end thereof to connect with the connecting supporter, and a fitting portion (12) with a fitting hole (13) defined therein formed at the other end of the connecting member (10).
The spindle (20) has a middle portion fitted in the corresponding fitting hole (13) and two opposite end portions respectively formed with two thread portions (211, 221).
The pair of retaining plates (30) are respectively defined with two central holes (31) and mounted around the opposite end portions of the spindle (20), each retaining plate (30) having a first retaining indentation (32), a second retaining indentation (33), a first positioning recess (34), and a second positioning recess (35) defined therein.
Each one of the pair of supporting units (40) has an upright portion (41) securely fixed on the backside of the display panel, and a horizontal portion (42) defined with a central hole (421) and mounted around one of the opposite ends of the spindle (20) at outside of the retaining plate 30. Each horizontal portion (42) includes a fixing hole (422) defined at one side adjacent the central hole (421), a recess (423) defined at an upper end thereof, and a positioning piece (424) formed at a lower end thereof extending inwards and passing through the second retaining indentation (33).
The interior springs (50) are torsional springs and respectively mounted around the opposite ends of the spindle (20) between the corresponding connecting members (10) and the retaining plates (30), wherein each one of the spring (50) has a first end (51) thereof biased against the connecting portion (11) of the connecting member (10), and a second end (52) thereof disposed in the second positioning recess (35).
The exterior springs (60) are also torsional springs mounted around the opposite ends of the spindle (20) at outsides of the supporting units (40) respectively. A first end (61) of the exterior springs (60) is inserted into the securing hole (422) of the horizontal portion (42) of the supporting unit 40. A second end (62) of the exterior springs (60) is extended through the recess (423) defined in the horizontal portion (42) of the supporting unit (40) and inserted into the first positioning recess (34) of the poison-limited plate (30).
The screw nuts (70) are threadingly engaged around the thread portion (211, 221) at the opposite ends of the spindle (20), respectively, and press against the outsides of the exterior torsion springs (60).
In the perfect working status, a liquid crystal display with the hinge device as described above is able to be adjusted and retained at any desired angle, due to the design of the cooperation between the interior and exterior springs and the retaining plates provided at the opposite sides. The support unit is also completely supported at the backside of the LCD, so as to minimize the size. However, the structure of the above described hinge device of the prior art is complicated with too many parts and accessories, i.e. the production cost of the hinge device is increased, and the possibility of trouble is also increased so that the technological level/cost is high.
Therefore, it is an objective of the invention to provide an improved hinge device for a flat panel display to mitigate and/or obviate the aforementioned problems.